JP3282010B2 - Toner and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a recording method utilizing an electrophotographic method, an electrostatic recording method, a magnetic recording method or the like, and an image forming method. For more information,
The present invention, after forming a toner image on the electrostatic latent image carrier in advance,
The present invention relates to a toner used for a copying machine, a printer, and a facsimile, which forms an image by being transferred onto a transfer material, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, many methods have been known as electrophotography. In general, a photoconductive substance is used to form an electric latent image on an image carrier (photoreceptor) by various means. After forming the latent image, the latent image is developed with a toner to form a visible image.If necessary, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat, pressure, or the like. To obtain a copy.

As a method for visualizing an electric latent image, a cascade developing method, a magnetic brush developing method, a pressure developing method and the like are known. Further, a method is also used in which a magnetic toner is used and a rotating sleeve having a magnetic pole disposed at the center is used to fly between the photosensitive member and the sleeve by an electric field.

The one-component developing system does not require carrier particles such as glass beads and iron powder as in the two-component developing system, so that the developing device itself can be reduced in size and weight. Further, in the two-component developing method, since it is necessary to keep the toner concentration in the carrier constant, a device for detecting the toner concentration and supplying a necessary amount of toner is required. Therefore, the developing device also becomes large and heavy here. In the one-component developing system, such an apparatus is not required, so that the apparatus can be made small and light, which is preferable.

[0005] In recent years, LED and LBP printers have become the mainstream in the printer market, and the direction of technology has been increased to higher resolution, that is, from 240, 300 dpi to 400, 600, 800 dpi. ing. Accordingly, higher definition has been required for the developing system. In addition, the functions of the copying machine have been advanced, and the digital copying machine is moving toward digitalization. In this direction, a method of forming an electrostatic charge image with a laser is mainly used, so that the direction is also moving toward a higher resolution, and a high-resolution and high-definition developing method is required similarly to a printer. . For this reason, the particle size of toner has been reduced, and Japanese Patent Application Laid-Open Nos.
JP-A-91156, JP-A-2-214156, JP-A-2-284158, JP-A-3-181952
And Japanese Patent Application Laid-Open No. 4-162048 propose a toner having a specific particle size distribution and a small particle size.

The toner image formed on the photoreceptor in the developing step is transferred to a transfer material in a transfer step, and the transfer residual toner remaining on the photoreceptor is cleaned in a cleaning step.
The toner is stored in the waste toner container. For this cleaning step, conventionally, blade cleaning, fur brush cleaning, roller cleaning, and the like have been used. From the viewpoint of the apparatus, the provision of such a cleaning apparatus inevitably increases the size of the apparatus, which has been a bottleneck when aiming for a more compact apparatus. Furthermore, from the viewpoint of ecology, a system with a small amount of waste toner is desired in terms of effective utilization of the toner, and a toner having good transfer efficiency has been demanded.

Regarding the improvement of transfer efficiency, Japanese Patent Publication No.
No. 13945, a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle to obtain a spherical toner, Japanese Patent Publication No. 36-10231, Japanese Patent Publication No. Sho 59-5
No. 3856, JP-A-59-61842, etc., a spherical toner, a non-spherical polymer toner by hetero-aggregation of emulsion polymer particles, etc. However, it is not yet sufficient in terms of durability and development stability after long-term repeated use.

Japanese Unexamined Patent Publication (Kokai) No. 61-279864 proposes a toner in which the shape factors SF-1 and SF-2 are specified. However, there is no description about transfer in this publication, and as a result of carrying out the examples, the transfer efficiency is low, and further improvement is required.

Further, Japanese Patent Application Laid-Open No. 63-235953 proposes a magnetic toner which is made spherical by a mechanical impact force. However, the transfer efficiency is still inadequate and further improvements are needed. As described above, attempts have been made to make conventional pulverized toner particles spherical by mechanical impact or heat, but there remains a problem in developing stability after long-term repeated use.

In recent years, from the viewpoint of environmental protection, the primary charging and transfer process using a corona discharge, which has been conventionally used, to the primary charging and transfer process using a photosensitive member contact member are becoming mainstream.

For example, JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to the contact charging method and the contact transfer method, but contact the conductive elastic roller with the electrostatic latent image carrier,
The electrostatic latent image carrier is uniformly charged while applying a voltage to the conductive roller, and then a toner image is obtained by an exposure and development process, and then another voltage is applied to the electrostatic latent image carrier. The transfer material is passed through the conductive roller while pressing the conductive roller, and the toner image on the electrostatic latent image carrier is transferred to the transfer material. Then, a transfer image is obtained through a fixing process.

However, in such a roller transfer method that does not use corona discharge, the transfer member is brought into contact with the photosensitive member via the transfer member during transfer, so that the toner image formed on the photosensitive member is transferred to the transfer material. When the toner image is transferred, the toner image is pressed against the toner image, which causes a problem of partial transfer failure called so-called missing transfer (see FIG. 5).

Further, as the diameter of the toner becomes smaller, the adhesion force (mirror image force, van der Waals force, etc.) of the toner particles to the photoreceptor becomes larger than the Coulomb force applied to the toner particles in the transfer. As a result, the transfer residual toner tends to increase.

Further, in the roller charging system, the physical and chemical action on the surface of the electrostatic latent image carrier due to the discharge generated between the charging roller and the electrostatic latent image carrier is larger than in the corona charging system. In particular, in the combination with the organic photoreceptor / blade cleaning, abrasion due to deterioration of the photoreceptor surface is likely to occur, and there is a problem in the life (direct charging /
The combination of organic photoreceptor / one-component magnetic developing method / contact transfer / blade cleaning makes it easy to reduce the cost and size and weight of an image forming apparatus. , Printer, facsimile, etc. ).

Accordingly, it has been required that the toner and the photoreceptor used in such an image forming method have excellent releasability.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner and an image forming method which solve the above-mentioned problems of the prior art.

That is, an object of the present invention is to provide excellent transferability,
An object of the present invention is to provide a toner and an image forming method in which the amount of residual toner is small and no omission occurs during transfer even in a roller transfer method, or these phenomena are suppressed.

It is a further object of the present invention to provide a toner and an image forming method that achieve both high image density, low fog, stable developability, and excellent transfer efficiency at the same time, even after printing for a long period and after printing a large number of sheets. .

It is a further object of the present invention to provide a toner and an image forming apparatus which are excellent in releasing property and slipperiness, have less of these functions for a long time and after printing many sheets, and have a long life. It is to provide a method.

It is a further object of the present invention to provide a toner and an image forming method in which abnormal charging or image defects due to contamination of a member pressed against an electrostatic latent image carrier does not occur or these phenomena are suppressed. It is in.

A further object of the present invention is to provide a toner and an image forming method in which a thin layer coating of a toner on a toner carrier is stable and excellent images can be obtained due to excellent charge controllability even in a low-temperature and low-humidity environment. Is to provide.

[0022]

According to the present invention, there is provided a toner having at least a binder resin and toner particles containing magnetic iron oxide and an inorganic fine powder, wherein the magnetic iron oxide comprises
(A) 0.4 to 4% by mass of silicon element based on iron element
It contained, and Fe / Si atomic ratio in the outermost surface of the magnetic iron oxide contains 0.05 to 10% by weight 1.2 to 4.0, or (b) aluminum element based on the iron element, and a magnetic oxide Fe / Al atomic ratio on the outermost surface of iron is 0.3 to 1
0.0 or (c) both the silicon element and the aluminum element are contained in the above ratio, and the Fe / Si atomic ratio and the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide are in the above ranges. The value of the shape factor SF-1 measured by the image analyzer of the toner is 110 <SF-1 ≦ 180, and the value of the shape factor SF-2 is 110 <SF-2 ≦ 140;
The ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 1.0 or less, and was measured by the BET method of the toner. The relationship between the specific surface area per unit volume Sb (m ² / cm ³ ) and the specific surface area per unit volume St (m ² / cm ³ ) calculated from the weight average particle diameter assuming that the toner is a true sphere is as follows. Condition 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5 and a toner image using the toner on an electrostatic latent image carrier. The present invention relates to an image forming method using an electrophotographic apparatus having a developing step of forming and a transfer step of transferring the toner image onto a transfer material while bringing a transfer member to which a voltage is applied into contact with a transfer material.

In the present invention, a toner having a SF-1 value of 120≤SF-1≤160 and a SF-2 value of 115≤SF-2≤140 is preferably used.

In the present invention, SF-
1, SF-2 is, for example, FE-SEM manufactured by Hitachi, Ltd.
Using (S-800), 100 toner images of 2 μm or more, which were enlarged 1000 times, were randomly sampled, and the image information was introduced into, for example, an image analyzer (Luzex III) manufactured by Nicole, via an interface. Analysis is performed, and the value calculated from the following equation is used as the shape factor SF-1, S
Defined as F-2.

[0025]

(Equation 1)

(Where MXLNG is the absolute maximum length of the particle,
PERIME indicates the perimeter of the particle, and AREA indicates the projected area of the particle. )

The shape factor SF-1 indicates the degree of roundness of the toner particles, and the shape coefficient SF-2 indicates the degree of unevenness of the toner particles.

When the shape factor SF-1 of the toner is 110 or less, when the spherical coefficient SF-2 of the toner is 110 or less, and when the value of the ratio B / A exceeds 1.0, cleaning failure generally occurs. And the shape factor S of the toner
When F-1 exceeds 180, the toner is separated from the sphere and approaches an irregular shape, the toner is easily crushed in the developing device, the particle size distribution fluctuates, the charge amount distribution tends to be broad, and ground fogging and reverse fogging occur. Cheap. On the other hand, if SF-2 exceeds 140, the transfer efficiency of the toner image at the time of transfer from the electrostatic image holding member to the transfer material is reduced, and the transfer of characters or line images during transfer is not preferable. At this time, a toner produced by a pulverization method is preferably used.

In FIG. 6, the value of the ratio B / A indicates the slope of a straight line passing through the origin.
0.9 (and even 0.35 to 0.85)
It is preferable to improve transferability while maintaining developability.

Further, by having the inorganic fine powder on the surface of the toner particles, the transfer efficiency is improved and the omission during transfer of characters and line images is improved. At this time, the specific surface area Sb per unit volume measured by the BET method and the specific surface area St per unit volume calculated from the weight average particle diameter (D ₄ ) assuming that the toner is a true sphere (St = 6 / D ₄ ) is 3.0 ≦ Sb / St ≦ 7.0 and Sb ≧ St ×
It is preferably 1.5 + 1.5, and Sb was 3.2 to 6.8 m ² / cm ³ (more preferably 3.4 to 6.8 m ² / cm ³ ).
6.3 m ² / cm ³ ).

When the above ratio is less than 3.0 times, the transfer efficiency is insufficient, and when it exceeds 7.0 times, the image density decreases. This is considered to be due to the fact that the inorganic fine particles added to the toner particles effectively act as a spacer between the toner particles and the toner image carrier.

The specific surface area of the toner in the above range can be achieved by controlling the specific surface area of the toner particles and the specific surface area, amount and mixing strength of the inorganic fine powder added to the toner particles. If the mixing strength is too high, the inorganic fine particles are embedded in the toner particles, and the transfer efficiency is insufficiently improved.

Further, since the inorganic fine powder is used effectively, the specific surface area Sr per volume of the toner particles is 1.2 to
2.5m ² / cm ³ (preferably 1.4~2.1m ² / c
m ³ ), which is 1.5 to 1.5 of the theoretical specific surface area per volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere.
It is better to be 2.5 times.

The specific surface area is preferably increased by 1.5 m ² / cm ³ or more by adding the inorganic fine powder. 1 nm to 100 nm of toner particles before adding inorganic particles
The 60% pore radius determined from the integrated pore area ratio curve of the pores is preferably 3.5 nm or less. At this time, the BET specific surface area Sb of the toner and the BET specific surface area S
The value of the ratio Sb / Sr of r is preferably in the range of 2 to 5.

[0035] These are those which reduce the number of pores in the toner particles that are equal to or larger than the primary particle size of the inorganic fine powder added to the toner particles, whereby the inorganic fine powder behaves more effectively and improves the transfer efficiency. it is conceivable that.

The specific surface area was determined by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device, Autosorb 1 (manufactured by Yuasa Ionics) according to the BET method, and calculating the specific surface area using the BET multipoint method. The 60% pore radius was determined from an integrated pore area ratio curve to the pore radius on the desorption side. In Autosorb 1, the calculation of the pore size distribution
rett, Joyner & Harenda (B.
J. H). J. Perform by the H method.

However, when the toner having the above-mentioned characteristics is subjected to an image test under a low temperature and low humidity environment,
It has been found that the uniformity of the thin layer coat of the toner on the toner carrier is likely to be disturbed by continuous image formation, and image defects such as blurred / wavy unevenness are likely to appear on the solid image.

The present inventors have found that the instability of the thin toner layer coat occurs because the charge amount per surface area of the toner tends to be higher than that of the conventional toner due to the shape of the toner. I found it. Although the cause is not necessarily clear, frictional charging with the charging member is performed at more sites on the toner surface due to less irregularities on the toner surface, and the charging opportunity substantially increases. Is to control the toner to a predetermined shape and physical properties by using heat and / or mechanical impact force. It is considered that deterioration of the surface of the body due to thermal / mechanical stress, deterioration of the charge control ability due to polishing of the surface of the magnetic body, and the like have occurred.

Therefore, by using a magnetic substance containing a predetermined amount of a silicon element and / or an aluminum element as the magnetic substance, the thermal stability of the magnetic substance can be improved, and the excessive charge of the toner can be leaked more efficiently. It has been found that the charge controllability of the toner can be improved more than before.

Although the mechanism is not always clear, 1) the dispersibility of the magnetic substance in the toner is improved, and the magnetic substance as a leak site functions more efficiently on the toner surface; and 2) the magnetic substance It is considered that the presence of the silicon element and / or the aluminum element on the surface improves the charge control ability of the magnetic substance on the toner surface.

When the magnetic toner is obtained through a mechanical or thermomechanical treatment, the magnetic material near the toner surface is considered to have a reduced charge control ability due to surface polishing or the like. In addition to the presence of silicon and / or aluminum in the magnetic material, the presence of the silicon and / or aluminum in the magnetic material also improves the charge control ability of the magnetic material on the toner surface. More preferred.

In the present invention, the magnetic iron oxide contains (a) 0.4 to 4% by mass of silicon element based on iron element, and / or (b) aluminum element contains 0.05 to 0.05 mass% based on iron element. By containing 10% by mass, the outermost surface or the composition and structure of the magnetic iron oxide can be controlled, and in the toner containing the magnetic iron oxide, the magnetic substance dispersibility in the toner and the charge control property in a low humidity environment. Excellent images can be obtained with a stable toner coat even after a long-term durability test and continuous use. If the magnetic iron oxide contains less than 0.4% by mass of silicon element based on iron element and less than 0.05% by mass of aluminum element based on iron element, a toner image analyzer Is 110 <SF-1 ≦ 1
80 and the value of SF-2 is 110 <SF-2 ≦ 1
40, the magnetic iron oxide is prevented from falling off from the toner due to mechanical impact when the toner is manufactured or processed so that the B / A is 1.0 or less, and the toner having such a shape is charged. The effect of the present invention for stabilizing characteristics cannot be obtained. When the magnetic iron oxide contains more than 4% by mass of the silicon element based on the iron element, the magnetic properties of the magnetic iron oxide are deteriorated or the surface of the magnetic iron oxide is vulnerable to mechanical impact. Even when the magnetic iron oxide contains more than 10% by mass of the aluminum element based on the iron element, it deteriorates the magnetic properties of the magnetic iron oxide or impairs the charging stability of the toner, especially the charging property under high humidity. .

It is preferable that the atomic ratio of Fe / Si on the outermost surface of the magnetic iron oxide is 1.2 to 4.0. Further, the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide is 0.3 to
It is preferably 10.0. If the Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide is larger than 4.0, the surface of the magnetic iron oxide is vulnerable to mechanical impact, and the chargeability of the toner changes after repeated long-term use. When the Fe / Si atomic ratio at the outermost surface of the magnetic iron oxide is smaller than 1.2, or when the Fe / Al atomic ratio at the outermost surface of the magnetic iron oxide is smaller than 0.3, the effect of the present invention can be obtained. Absent. If the atomic ratio of Fe / Al on the outermost surface of the magnetic iron oxide is larger than 10.0, there is a problem that the change in chargeability due to the environment of the toner becomes large.

Further, the iron element dissolution rate of the magnetic iron oxide is 20
The ratio (b / a) × 100 of the content b of the silicon element existing up to mass% and the total content a of the silicon element in the magnetic iron oxide is 4
4 to 84%, the ratio (c / c) of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element.
a) It is preferable that x100 is 10 to 55%. The content b of the silicon element existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass, and the total content a of the silicon element of the magnetic iron oxide
When the ratio (b / a) × 100 is smaller than 44% and the silicon element is present in a large amount in the central portion of the magnetic iron oxide, it is difficult to control the magnetic properties, and the production efficiency of the magnetic iron oxide tends to decrease. Become. The ratio (b / a) × 100 of the content b of the silicon element existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass and the total content a of the silicon element of the magnetic iron oxide is more than 84%. If the size is large, the surface of the magnetic iron oxide is vulnerable to mechanical impact, and the chargeability of the toner may change due to repeated long-term use. The ratio (c) between the content c of the silicon element existing on the surface of the magnetic iron oxide and the total content a of the silicon element a
When (a) × 100 is smaller than 10%, the effect of the present invention cannot be obtained. Ratio of the content c of silicon element present on the surface of the magnetic iron oxide to the total content of silicon element (c / a)
When x100 is larger than 55%, irregularities are conspicuous on the surface of the magnetic iron oxide, and the irregularities become fragments during the production of the toner, thereby reducing the dispersibility of the magnetic iron oxide in the toner and / or charging the toner. Reduce the nature.

In the present invention, the content of the silicon element on the surface of the magnetic iron oxide can be determined by the following method.
For example, about 3 liters of deionized water is placed in a 5 liter beaker and heated in a water bath to 50 to 60 ° C. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is added to the 5 liter beaker with the deionized water while washing with about 30 ml of deionized water. Next, while maintaining the temperature at about 60 ° C. and the stirring speed at about 200 rpm, dissolution of a silicon compound such as silicic acid on the surface of the magnetic iron oxide particles is started by adding a special grade sodium hydroxide to form a 1N sodium hydroxide solution. .
After 30 minutes from the start of dissolution, 20 ml was sampled.
Filter through a 1 μm membrane filter and collect the filtrate. The filtrate is quantified for silicon by plasma emission spectrometry (ICP). The content of silicon element corresponds to the concentration of silicon element per unit mass of magnetic iron oxide in sodium hydroxide solution (mg / liter).

In the present invention, the content of the silicon element (based on the iron element), the dissolution rate of the iron element, and the content of the silicon element in the dissolution rate can be determined by the following methods. For example, about 3 liters of deionized water is placed in a 5 liter beaker and heated in a water bath to 45 to 50 ° C. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is added to the 5 liter beaker with the deionized water while washing with about 30 ml of deionized water. Next, while maintaining the temperature at about 50 ° C. and the stirring speed at about 200 rpm, special grade hydrochloric acid is added to start dissolution. At this time, the concentration of the magnetic iron oxide is about 5 g / liter, and the aqueous hydrochloric acid solution is about 3N. 20 ml is sampled several times from the start of dissolution until it is completely dissolved and becomes transparent, filtered through a 0.1 μm membrane filter, and the filtrate is collected. The filtrate is analyzed by plasma emission analysis (IC
P) quantifies iron and silicon elements. The iron element dissolution rate for each sample is calculated by the following equation.

[0047]

(Equation 2)

The content and content of the silicon element for each sample are calculated by the following equations.

[0049]

(Equation 3)

The total content of the silicon element in the magnetic iron oxide corresponds to the concentration of the silicon element per unit mass (mg / liter) of the magnetic iron oxide after being completely dissolved.

The silicon element content of the magnetic iron oxide corresponds to the silicon element concentration (mg / liter) per unit mass of the magnetic iron oxide to be detected when the solubility of the magnetic iron oxide is 20%.

The total content of the silicon element of the magnetic iron oxide, the content of the silicon element existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass, and the content of the silicon element existing on the surface of the magnetic iron oxide are expressed as follows. The measurement method is as follows: (1) While dividing the sample of magnetic iron oxide into two, measuring the total content of the silicon element and the content of the silicon element in which the iron element dissolution rate is up to 20% by mass, A method of separately measuring the content of the silicon element present on the surface; and (2) measuring the content of the silicon element present on the surface, using the sample after the measurement, and then dissolving the iron element by 20 mass%. %, The amount obtained by subtracting the content of the silicon element present on the surface from the content of the silicon element present up to 10% and the amount obtained by subtracting the content of the silicon element present on the surface from the total content are measured. Content and dissolution rate of iron element are 20% by mass
There is a method of calculating the content of the silicon element existing up to now.

In the present invention, the Fe / Si atomic ratio and the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide can be determined by XPS measurement. In the present invention, an X-ray photoelectron spectroscopy device ESC is used as the XPS measurement device.
A LAB, 200-X type (manufactured by VG) was used, and the measurement was performed with an X-ray source of MgKα (300 W) and an analysis area of 2 × 3 mm.

In order to faithfully develop finer latent image dots for higher image quality, the toner particles have a weight average diameter of 4%.
It is preferable that it is between μm and 9 μm. 4μ weight average diameter
m, toner remaining on the photoreceptor due to a decrease in transfer efficiency is large, and further, it is likely to cause non-uniform unevenness of an image based on fog and poor transfer. Not preferred. If the weight average diameter of the toner particles exceeds 9 μm, characters and line images are likely to be scattered.

The average particle size and the particle size distribution of the toner are measured using a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter), and an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution, and PC9.
801 personal computer (manufactured by NEC) is connected, and the electrolyte is 1% NaCl using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON R-II
(Manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolytic aqueous solution 100 to 1
0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant in 50 ml,
Further, 2 to 20 mg of a measurement sample is added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more were measured using a 100 μm aperture as the aperture by the Coulter Counter TA-II. The volume distribution and number distribution were calculated. Then, a volume-based weight average particle diameter (D ₄ ) obtained from the volume distribution according to the present invention and a number-based length average particle diameter (D ₁ ) obtained from the number distribution were obtained.

The charge amount per unit volume (two-component method) of the toner according to the present invention is 30 to 80 C / m ³ (more preferably 40 to 70 C / m ³ ). It is preferable to improve the transfer efficiency in the transfer method using a member.

A method for measuring the charge amount (two-component tribo) of the toner according to the two-component method in the present invention is shown below (FIG. 4).

Under an environment of 23 ° C. and a relative humidity of 60%, a mixture of 9.5 g of carrier and 0.5 g of toner added to 9.5 g of carrier was used as a carrier in a polyethylene bottle having a capacity of 50 to 100 ml using EFV200 / 300 (made by Powder Tech). And shake by hand 50 times. Then, 1.0 to 1.2 g of the mixture is placed in a metal measuring container 22 having a 500-mesh screen 23 at the bottom, and a metal lid 24 is placed. At this time, the mass of the entire measurement container 22 is weighed and defined as W ₁ (g). Next, in a suction machine (at least a portion in contact with the measuring container 22 is an insulator), the pressure of the vacuum gauge 25 is adjusted to 2450 Pa (25
0 mmAq). In this state, suction is performed for one minute to remove the toner by suction. The potential of the electrometer 29 at this time is V
(Volts). Here, 28 is a capacitor whose capacity is C (μF). In addition, the mass of the entire measuring machine after suction is weighed and defined as W ₂ (g). The triboelectric charge amount (m
C / kg) is calculated as shown below.

The triboelectric charge (mC / kg) = CV / (W ₁ −W ₂ )

The binder resin used in the toner according to the present invention has a low molecular weight peak in the range of 3,000 to 15,000 in the GPC molecular weight distribution, which indicates that the shape of the toner produced by the pulverization method is thermomechanical. It is preferable for controlling by impact force. 1 low molecular weight peak
If it exceeds 5,000, it is difficult to control the shape factors SF-1 and SF-2 within the range of the present invention, and the transfer efficiency is not sufficiently improved. If it is less than 3,000, fusion is likely to occur during surface treatment. The molecular weight is measured by GPC (gel permeation chromatography). Specific GPC
Is measured using a sample obtained by extracting the toner with a THF (tetrahydrofuran) solvent for 20 hours using a Soxhlet extractor, and the column configuration is A
-801, 802, 803, 804, 805, 806,
807, and the molecular weight distribution can be measured using a standard polystyrene resin calibration curve.

A resin having a ratio (Mw / Mn) of 2 to 100 between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is preferable in the present invention.

The glass transition point Tg of the toner is preferably from 50 ° C. to 75 ° C. (more preferably, from 52 ° C. to 70 ° C.) from the viewpoints of fixability and storage stability.

The glass transition point Tg of the toner according to the present invention
For example, a Perkin Elmer DSC-
The measurement is performed using a high-precision internal heating type input compensation type differential scanning calorimeter such as 7. The measurement method is ASTM D3418-8.
Perform according to 2. In the present invention, the sample is heated once to obtain a pre-history, then rapidly cooled, and then cooled again at a temperature rate of 10 ° C / m.
in, a DSC curve measured when the temperature is raised in the range of 0 to 200 ° C.

Examples of the type of the binder resin used in the present invention include a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and a substituted product thereof; styrene-p-chlorostyrene copolymer. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene copolymers such as indene copolymers Coalescence; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin , Polyvinyl butyral, terpene resin, cumarone indene resin, petroleum resin and the like can be used. Further, a crosslinked styrene resin is also a preferable binder resin.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, and the like; and vinyl chloride;
Vinyl esters such as vinyl acetate, vinyl benzoate and the like, for example, ethylene olefins such as ethylene, propylene, butylene and the like; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
For example, vinyl monomers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and the like, or a vinyl monomer such as vinyl monomers, may be used alone or in combination. Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene or the like; for example, ethylene glycol diacrylate, ethylene glycol Dimethacrylate,
Carboxylic esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinylether, divinylsulfide, divinylsulfone; and compounds having three or more vinyl groups; Can be used alone or as a mixture.

Examples of the binder resin for toner used for pressure fixing include low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, higher fatty acid, and polyamide. Resins and polyester resins. These are preferably used alone or as a mixture.

It is also preferable to include the following waxes in the toner from the viewpoint of improving the releasability from the fixing member at the time of fixing and improving the fixing property. Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc., with derivatives including oxides and block copolymers with vinyl monomers , Graft-modified products.

In addition, alcohols, fatty acids, acid amides,
Esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, mineral waxes, petrolactam and the like can also be used.

In the magnetic toner of the present invention, a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It is preferable to use them. The charge control agent makes it possible to control the amount of charge optimally according to the development system. In particular, in the present invention, the balance between the particle size distribution and the amount of charge can be further stabilized. The following substances control the toner to be negatively charged.

For example, organic metal complexes and chelate compounds are effective, and examples thereof include monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The following substances are controlled to be positively charged.

Modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium salts which are analogs thereof Onium salts such as, for example, these lake pigments, triphenylmethane dyes and these lake pigments (as the lacking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid) , Ferrocyanide, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyl Diorgano tin borate such as Suzuboreto; can be used in combination singly or two or more kinds.

The above charge control agents are preferably used in the form of fine particles. In this case, the number average particle size of these charge control agents is particularly preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner, it is preferable to use 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, based on 100 parts by weight of the binder resin.

As the colorant used in the present invention, a black colorant which is toned with carbon black, a magnetic substance, and a yellow / magenta / cyan colorant shown below is used.

Examples of the yellow colorant include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 97, 109, 1
10, 111, 120, 127, 128, 129, 14
7, 168, 174, 176, 180, 181, 191
Etc. are preferably used.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66, etc. can be particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by mass per 100 parts by mass of the resin.

The magnetic iron oxide of the toner according to the present invention is made of resin 10
It is used by adding 30 to 200 parts by mass to 0 parts by mass.

Examples of the magnetic substance include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. In the present invention, triiron tetroxide, γ-iron oxide, etc. Magnetic iron oxide containing iron oxide as a main component is preferable, and (a) 0.4 to 4% by mass of silicon element is contained based on iron element, and / or (b) aluminum element is 0% based on iron element. .05-10
It is necessary that the content be contained by mass%.

Preparation of magnetic iron oxide containing 0.4 to 4% by mass of silicon element according to the present invention and / or 0.05 to 10% by mass of aluminum element based on iron element For example, a known method is used. For example, when a ferrous salt aqueous solution is oxidized at 60 to 90 ° C. to generate magnetic iron oxide, a silicon compound aqueous solution and / or
Alternatively, there is a method in which an aqueous solution of an aluminum compound is mixed in a reaction solution before the oxidation reaction to carry out the oxidation reaction, dropped during the oxidation reaction, or added after the oxidation reaction of the magnetic iron oxide is completed to further react.

Further, the distribution of the silicon element and the aluminum element present in the magnetic iron oxide is continuously increased from the inside of the magnetic iron oxide particles toward the surface by the method disclosed in Japanese Patent Application Laid-Open No. 5-213620. Alternatively, it is preferable to increase stepwise.

[0083] These magnetic iron oxides are obtained by adding B
The ET specific surface area is preferably 3 to 35 m ² / g, particularly 5 to 5 m ² / g.
A magnetic powder having 30 m ² / g and a Mohs hardness of 5 to 7 is preferable.

The shape of the magnetic material is octahedron, hexahedron,
There are spheres, needles, scales, etc., but octahedrons, hexahedrons, spheres, irregular shapes and the like with little anisotropy are preferred in order to increase the image density. The average particle size of the magnetic material is 0.05 to
1.0 μm is preferred, and more preferably 0.1 to 0.1 μm.
6 μm, and more preferably 0.1 to 0.4 μm.

The amount of the magnetic substance is 3 with respect to 100 parts by mass of the binder resin.
0 to 200 parts by mass, preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass. If the amount is less than 30 parts by mass, in a developing device that uses a magnetic force to transport the toner, the transportability is insufficient, and the developer layer on the developer carrier tends to be uneven, resulting in image unevenness. , The image density tends to decrease. On the other hand, if it exceeds 200 parts by mass, a problem tends to occur in the fixing property.

As the inorganic fine powder contained in the toner of the present invention, known ones may be used. However, silica, alumina, and silica are preferred for improving charging stability, developing property, fluidity, and storage stability.
It is preferable to be selected from titania or a composite oxide thereof. Furthermore, silica is more preferable. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide and an alkoxide, and a so-called wet silica produced from an alkoxide, a water glass and the like, and a dry silica called a fumed silica can be used. However, dry silica having less silanol groups on the surface and in the interior of the silica fine powder and having less production residues such as Na ₂ O and SO ₃ ^2- is preferred. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the manufacturing process. Is also included.

[0087] Inorganic fine powder used in the present invention is the specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more, particularly given good results in the range of 50 to 400 m ² / g, the toner 100 mass It is particularly preferable to use 0.1 to 8 parts by mass, preferably 0.5 to 5 parts by mass, more preferably more than 1.0 to 3.0 parts by mass of the silica fine powder with respect to parts.

The inorganic fine powder used in the present invention comprises:
The primary particle size is preferably 30 nm or less.

The inorganic fine powder used in the present invention comprises:
Silicon varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, other organosilicon compounds, organic It is possible and preferable to use a treating agent such as a titanium compound or a combination of various treating agents.

In order to maintain a high charge amount and achieve a low consumption and a high transfer rate, it is more preferable that the inorganic fine powder be treated with at least silicone oil.

In the present invention, transferability and / or
Alternatively, in order to improve the cleaning property, in addition to the inorganic fine powder, the primary particle diameter further exceeds 30 nm (preferably, the specific surface area is less than 50 m ² / g), and more preferably, 5 μm or less.
0 nm or more (preferably, the specific surface area is less than 30 m ² / g)
It is also a preferred embodiment to further add inorganic or organic particles having a nearly spherical shape. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, and spherical resin particles are preferably used.

In the toner of the present invention, other additives such as lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder; cerium oxide powder, silicon carbide Powder,
Abrasives such as strontium titanate powder; fluidity imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or conductivity imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder, Organic and inorganic fine particles of opposite polarity can also be used in small amounts as a developer improver.

A known method is used for producing the toner according to the present invention. For example, a binder resin, a wax,
Metal salts or metal complexes, pigments and dyes as colorants,
Alternatively, a magnetic material, a charge control agent, if necessary, and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, a kneader, or an extruder. A metal compound, a pigment, a dye, and a magnetic substance are dispersed or dissolved in a resin mixed with each other, and after cooling and solidifying, pulverization and classification are performed to obtain the toner according to the present invention. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

Examples of the surface treatment include a hot water bath method in which the pulverized toner particles are dispersed in water and heated, a heat treatment method in which the toner particles are passed through a hot air flow, and a mechanical impact method in which mechanical energy is applied for treatment. In the present invention, in the mechanical impact method, the processing temperature is set to the glass transition point Tg of the toner particles.
Thermo-mechanical shock applying a nearby temperature (Tg ± 10 ° C)
It is preferable from the viewpoint of prevention of aggregation and productivity. More preferably, the heat treatment is performed at a temperature in the range of the glass transition point Tg ± 5 ° C. of the toner, in order to reduce pores having a radius of 10 nm or more on the surface, effectively use the inorganic fine powder, and improve transfer efficiency. It is valid.

Further, the present invention is effective when the surface of the image carrier is mainly composed of a polymer binder. For example, when a protective film mainly composed of resin is provided on an inorganic image carrier such as selenium or amorphous silicon, or as a charge transport layer of a function-separated organic image carrier, a surface layer composed of a charge transport material and a resin is used. In some cases, a protective layer as described above may be further provided thereon. Means for imparting releasability to such a surface layer include using a resin having a low surface energy as a resin constituting the film, water repellency,
Additives that impart lipophilicity, and powdery materials having high releasability are dispersed. Is achieved by introducing a fluorine-containing group, a silicon-containing group, or the like into the structure of the resin. , A surfactant or the like may be used as an additive. Examples thereof include compounds containing a fluorine atom, that is, powders of polytetrafluoroethylene, polyvinylidene fluoride, carbon fluoride and the like. Among them, polytetrafluoroethylene is particularly preferable. In the present invention, dispersion of a releasable powder such as a fluororesin in the outermost surface layer is particularly preferred.

By these means, the contact angle of the surface of the image carrier with water can be set to 85 degrees or more (preferably 90 degrees or more). If it is less than 85 degrees, the toner and the toner carrier are likely to deteriorate due to durability.

In order to incorporate these powders on the surface, a layer in which the powders are dispersed in a binder resin is provided on the outermost surface of the image carrier, or an organic material originally composed mainly of resin. In the case of an image carrier, the powder may be dispersed in the uppermost layer without providing a new surface layer.

The amount of the powder added to the surface layer is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, based on the total mass of the surface layer. When the amount is less than 1% by mass, the effect of improving the durability of the toner and the toner carrier is insufficient, and
Exceeding the range is not preferred because the strength of the film is reduced and the amount of light incident on the image carrier is significantly reduced.

The present invention is particularly effective when the charging means is a direct charging method in which the charging member is brought into contact with the image carrier. As compared with corona discharge or the like in which the charging means does not come into contact with the image carrier, the load on the surface of the image carrier is large, so that the improvement effect is remarkable in terms of the life of the image carrier.

One preferred embodiment of the image carrier used in the present invention will be described below.

Examples of the conductive substrate include metals such as aluminum and stainless steel, aluminum alloys and indium oxide.
Cylindrical cylinders and films of plastic having a coating layer of a tin oxide alloy or the like, paper impregnated with conductive particles, plastic, plastic having a conductive polymer, and the like are used.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coating properties are improved, the substrate is protected, defects on the substrate are covered,
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate, protecting the photosensitive layer against electrical destruction, and the like. The undercoat layer is made of polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue,
It is formed of a material such as gelatin, polyurethane, and aluminum oxide. The film thickness is usually 0.1 to 10 μm,
Preferably it is about 0.1 to 3 μm.

The charge generation layer is made of an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, a squarylium dye, a pyrylium salt, a thiopyrylium salt, a triphenylmethane dye, selenium,
A charge generating substance such as an inorganic substance such as amorphous silicon is dispersed in an appropriate binder and formed by coating or vapor deposition. The binder can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacryl resin, phenol resin, silicone resin, epoxy resin, vinyl acetate resin, etc. Is mentioned. The amount of the binder contained in the charge generation layer is 80% by mass.
Hereinafter, it is preferably selected from 0 to 40% by mass. Further, the thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transporting layer is formed by dissolving a charge transporting substance in a solvent together with a binder resin if necessary, and applying the solution. The film thickness is generally 5 to 40 μm. As the charge transport substance, biphenylene,
Polycyclic aromatic compounds having a structure such as anthracene, pyrene, and phenanthrene; nitrogen-containing cyclic compounds such as indole, carbazole, oxadiazole, and pyrazoline;
Hydrazone compounds, styryl compounds, selenium, selenium
Tellurium, amorphous silicon, cadmium sulfide and the like.

The binder resin for dispersing these charge transporting substances includes polycarbonate resin, polyester resin, polymethacrylate, polystyrene resin, and the like.
Examples include resins such as acrylic resins and polyamide resins, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

Further, a protective layer may be provided as a surface layer. As the resin for the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins alone or
It is used in combination of more than one species.

In addition, conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals, metal oxides, etc., preferably, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide-coated titanium oxide, tin-coated indium oxide, There are ultrafine particles such as antimony-coated tin oxide and zirconium oxide. These may be used alone or as a mixture of two or more. Generally, when particles are dispersed in the protective layer, it is necessary that the particle diameter of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles, and the particles are dispersed in the protective layer in the present invention. The particle size of the conductive and insulating particles is preferably 0.5 μm or less. The content in the protective layer is preferably from 2 to 90% by mass, more preferably from 5 to 80% by mass, based on the total mass of the protective layer. The thickness of the protective layer is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm.

The surface layer can be applied by spray coating, beam coating or permeation coating of the resin dispersion.

Hereinafter, the contact transfer step applicable to the image forming method of the present invention will be specifically described.

In the contact transfer step, the developed image is electrostatically transferred onto the transfer material while the transfer means is in contact with the electrostatic image carrier via the transfer material. The contact pressure of the transfer means is a linear pressure. It is preferably at least 2.9 N / m (3 g / cm), more preferably 19.6 N / m (20 g / cm).
That is all. When the linear pressure as the contact pressure is 2.9 N / m (3
g / cm) is not preferred because transfer deviation of the transfer material and transfer failure are likely to occur.

Further, as the transfer means in the contact transfer step, an apparatus having a transfer roller or a transfer belt is used. The transfer roller includes at least a core metal and a conductive elastic layer, and the conductive elastic layer has a volume resistance of 10 ⁶ to 1 such as urethane or EPDM in which a conductive material such as carbon is dispersed.
It is made of an elastic material of about 0 ¹⁰ Ωcm.

The present invention is particularly effectively used in an image forming apparatus in which the surface of a latent image carrier (photoreceptor) is an organic compound. That is, when the organic compound forms the surface layer of the photoreceptor, the adhesiveness to the binder resin contained in the toner particles is superior to other photoreceptors using an inorganic material, and the transferability is further reduced. This is because there is a tendency to do so.

Examples of the surface material of the photoreceptor according to the present invention include silicone resin, vinylidene chloride, ethylene-vinyl chloride, styrene-acrylonitrile, styrene-methyl methacrylate, styrene, polyethylene terephthalate and polycarbonate. Without being limited to these, other monomers or copolymers and blends of the above-mentioned binder resins can also be used.

The present invention is particularly effectively used for an image forming apparatus having a small-diameter photosensitive member having a diameter of 50 mm or less. That is, in the case of a small-diameter photosensitive member, the curvature for the same linear pressure is large, and the concentration of pressure in the contact portion is likely to occur. Although it is considered that the same phenomenon occurs in the belt photoreceptor, the present invention has a curvature radius of 25 at the transfer portion.
This is also effective for an image forming apparatus having a size of less than mm.

Further, the toner of the present invention is set so that the closest gap between the image carrier and the toner carrier is larger than the thickness of the toner layer on the toner carrier by the member for regulating the toner on the toner carrier. It is particularly preferable that the member for regulating the toner on the toner carrier is regulated by an elastic member which is in contact with the toner carrier via the toner from the viewpoint of uniformly charging the toner.

Further, the surface roughness of the toner carrier used in the present invention is 0.2 to 0.2 in terms of JIS center line average roughness (Ra).
It is preferably in the range of 3.5 μm.

When Ra is less than 0.2 μm, the charge amount on the toner carrier increases, and the developability becomes insufficient. When Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer on the toner carrying member, resulting in uneven image density. More preferably, it is preferably in the range of 0.5 to 3.0 μm.

Further, since the toner of the present invention has a high chargeability, it is desirable to control the total charge amount of the toner at the time of development, and the surface of the toner carrier according to the present invention contains conductive fine particles and / or a lubricant. It is preferable to be covered with a dispersed resin layer.

Examples of the conductive fine particles contained in the resin layer covering the surface of the toner carrier include conductive metal oxides such as carbon black, graphite, and conductive zinc oxide and metal double oxides, alone or in combination of two or more. It is preferably used. Further, as the resin in which the conductive fine particles are dispersed, phenolic resin, epoxy resin, polyamide resin, polyester resin, polycarbonate resin,
Known resins such as polyolefin resins, silicone resins, fluorine resins, styrene resins, and acrylic resins are used. In particular, a thermosetting or photocurable resin is preferable.

When the one-component developing method is used in the present invention, the layer thickness smaller than the closest distance (between SD) between the toner carrier and the latent image carrier on the toner carrier to obtain high image quality. Then, it is preferable that the development is performed in a development step of applying a magnetic toner and applying an alternating electric field to perform development.

In the present invention, it is preferable from the viewpoint of environmental protection that the charging member and the transfer member are in contact with the photosensitive member so that ozone is not generated.

The preferable process conditions when the charging roller is used are that the contact pressure of the roller is 5 to 500 g /
cm, when a voltage obtained by superimposing an AC voltage on a DC voltage is used, AC voltage = 0.5 to 5 kVpp, AC frequency =
50 to 5 kHz, DC voltage = ± 0.2 to ± 5 kV.

Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means have the effects of eliminating the need for high voltage and reducing the generation of ozone.

The material of the charging roller and the charging blade as the contact charging means is preferably a conductive rubber, and a release coating may be provided on the surface thereof. As the release coating, a nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), a fluoroacrylic resin, or the like can be used.

Next, the image forming method of the present invention will be specifically described with reference to the drawings.

In FIG. 1, reference numeral 100 denotes a photosensitive drum, around which a primary charging roller 117, a developing device 140, a transfer charging roller 114, a cleaner 116, a register roller 124 and the like are provided. And the photosensitive drum 100
Is charged to -700 V by the primary charging roller 117 (applied voltage is AC voltage -2.0 kVpp, DC voltage -700 Vdc). The photosensitive drum 100 is exposed by irradiating the photosensitive drum 100 with a laser beam 123 by a laser generator 121. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component magnetic toner by a developing device 140,
Transfer roller 1 in contact with photosensitive drum via transfer material
The image is transferred onto a transfer material by. The transfer material bearing the toner image is carried to a fixing device 126 by a conveyor belt 125 or the like, and is fixed on the transfer material. Further, the toner partially left on the electrostatic latent image carrier is cleaned by the cleaning unit 116.

As shown in FIG. 2, the developing device 140 is provided with a cylindrical toner carrier 102 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel in the vicinity of the photosensitive drum 100. The gap between the photosensitive drum 100 and the developing sleeve 102 is maintained at about 300 μm by a sleeve / drum gap holding member (not shown). Further, a stirring rod 141 is provided in the developing device. Inside the developing sleeve, a magnet roller 104 is fixed and disposed concentrically with the developing sleeve 102. However, the developing sleeve 102 is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the figure. S ₁ is for development, N ₁ is for controlling the amount of toner coating, S ₂ is for taking in / conveying toner, and N ₂ is for preventing toner blowing. I have. The elastic blade 1 serves as a member for regulating the amount of magnetic toner adhered to and conveyed to the developing sleeve 102.
03 is provided and the developing sleeve 10 of the elastic blade 103 is provided.
The contact pressure with respect to 2 controls the amount of toner conveyed to the development area. In the developing area, a DC and AC developing bias is applied between the photosensitive drum 100 and the developing sleeve 102, and the toner on the developing sleeve flies on the photosensitive drum 100 according to the electrostatic latent image to become a visible image.

[0128]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Production Examples and Examples, but this does not limit the present invention in any way. All parts in the following formulations are parts by mass.

[Production Example 1 of Magnetic Iron Oxide] Sodium silicate was added to an aqueous ferrous sulfate solution so that the content ratio of silicon to iron was 1.9%. An aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 equivalent of a sodium hydroxide solution. While maintaining the pH of the aqueous solution at about 9, air was blown therein to perform an oxidation reaction at 80 ° C. to prepare a slurry liquid for generating a seed crystal serving as a core of the magnetic iron oxide particles.

Then, 1.1 equivalents of an aqueous ferrous sulfate solution with respect to the initial alkali amount (sodium component of sodium silicate and sodium component of sodium hydroxide) were added to the slurry, and the pH of the slurry was adjusted to 8 The oxidation reaction was proceeded while blowing air while maintaining the temperature at about the same level, the pH was adjusted at the end of the oxidation reaction, and the silicic acid component was unevenly distributed on the surface of the magnetic iron oxide. The magnetic iron oxide particles generated are washed, filtered,
A magnetic iron oxide A containing 1.9 mass% of silicon element based on iron element after being dried and then subjected to an analysis treatment for loosening agglomeration
I got

Fe / Fe on the outermost surface of the magnetic iron oxide A
The Si atomic ratio was 4.0.

Table 1 shows data obtained by measuring the amounts of iron and silicon dissolved every 10 minutes. From this, the content b of the silicon element present when the iron dissolution rate of the magnetic iron oxide is up to 20% by mass is about 37.8 mg / l, and the total content a of the silicon element in the magnetic iron oxide a is 62.2 mg / l. Ratio (b / a) × 100 is 60.8%, and the content c of the silicon element derived from the silicon compound existing on the surface of the magnetic iron oxide eluted with the alkali is 16.2 mg / liter, which is The ratio (c / a) × 100 to the total content a is 2
6.0%.

[Production Example 2 of Magnetic Iron Oxide] Production Example 1 of Magnetic Iron Oxide was the same as Production Example 1 of Magnetic Iron Oxide except that sodium silicate was added so that the content ratio of silicon to iron was 0.5%. In the same manner as in the above, magnetic iron oxide B was obtained. Table 3 shows the characteristics of the magnetic iron oxide B.

[Production Example 3 of Magnetic Iron Oxide] An aqueous solution containing ferrous hydroxide was prepared by mixing 0.95 equivalent of caustic soda solution with respect to iron ions in an aqueous solution of ferrous sulfate. Thereafter, sodium silicate was added so as to be 1.2% in terms of silicon element with respect to iron element. Then
Magnetic iron oxide particles containing a silicon element were produced by conducting air oxidation at 90 ° C. of an aqueous ferrous salt solution containing iron hydroxide to cause an oxidation reaction.

Further, 0.2% of sodium silicate was added to this slurry.
1.05 equivalents of an aqueous solution of caustic soda in which (silicon element equivalent to iron element) was dissolved was added to the remaining iron ions, and the oxidation reaction was further promoted while heating at a temperature of 90 ° C. to contain the silicon element. Magnetic iron oxide particles were produced.

The magnetic iron oxide particles produced are washed by a conventional method, filtered and dried, and then subjected to a crushing treatment for loosening agglomeration to obtain a magnetic iron oxide containing 1.4% by mass of silicon element based on iron element. C was obtained.

Fe / Fe on the outermost surface of this magnetic iron oxide C
The Si atomic ratio was 1.7.

Table 2 shows data obtained by measuring the dissolution amounts of iron element and silicon element every 10 minutes. From this, the content b of the silicon element existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by mass is about 28.4 mg / l, and the total content of the silicon element a48.9 mg / l of the magnetic iron oxide is The ratio (b / a) × 100 is 58.1%, and the ratio (c / a) between the content c7.3 mg / liter of the silicon element present on the surface of the magnetic iron oxide and the total content a of the silicon element (c / a) × 100
Was 14.9%.

[Magnetic Iron Oxide Production Examples 4 to 6] After the magnetic iron oxide particles produced in Magnetic Iron Oxide Production Example 3 were washed by a conventional method, the aluminum element was added to the slurry as an aluminum element in the slurry before filtration. Aluminum sulfate was added to adjust the pH to about 7, and a surface treatment of magnetic iron oxide was performed as aluminum hydroxide.

When performing the surface treatment, the amount of aluminum sulfate was adjusted so that the content ratio of aluminum element to iron element was 0.05.
%, 0.3% and 1.8%, and then filtered and dried in the same manner as in Preparation Example 3 of magnetic iron oxide, and then subjected to a crushing treatment for loosening aggregation. , Magnetic iron oxides D, E and F were obtained. Table 3 shows the characteristics of the magnetic iron oxides D, E, and F.

[Production Example 7 of Magnetic Iron Oxide] In a ferrous sulfate aqueous solution, 1.1 equivalents of a caustic soda solution and 0.05 equivalents of an aluminum sulfate aqueous solution were mixed with respect to iron ions, and ferrous hydroxide was added. An aqueous solution was prepared.
Air was blown in and an oxidation reaction was performed at 80 ° C. to generate magnetic iron oxide particles.

The produced magnetic iron oxide particles are washed, filtered and dried by a conventional method, and then subjected to a crushing treatment for loosening agglomeration.
Magnetic iron oxide G containing 2.4% by mass of aluminum element based on iron element was obtained.

Fe / Fe on the outermost surface of this magnetic iron oxide G
The Al atomic ratio was 2.5.

[Production Example 8 of Magnetic Iron Oxide] A caustic soda solution in an amount of 1.05 equivalent to iron ions was mixed with an aqueous solution of ferrous sulfate to prepare an aqueous solution containing ferrous hydroxide. The ferrous salt aqueous solution containing iron hydroxide contains 90
By oxidizing air by passing air at ℃,
Magnetic iron oxide particles substantially free of silicon and aluminum were produced.

The produced magnetic iron oxide particles are washed, filtered and dried by a conventional method, and then subjected to a crushing treatment for loosening agglomeration.
Magnetic iron oxide H substantially free of silicon and aluminum was obtained.

[0146]

[Table 1]

[0147]

[Table 2]

[0148]

[Table 3]

(Toner Production Example 1) Magnetic Iron Oxide A (Magnetic Iron Oxide Production Example 1) 100 parts Styrene-butyl acrylate-butyl maleate half ester copolymer (low molecular weight side peak: about 8000, glass transition) (Point Tg: 60 ° C.) 100 parts ・ Chromium complex of monoazo dye (negative charge control agent) 1 part ・ Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender,
Melted and kneaded with a twin-screw extruder heated to ℃, the cooled kneaded material is coarsely pulverized with a hammer mill, the coarsely pulverized material is finely pulverized with a jet mill, and the obtained finely pulverized material is multi-divided using the Coanda effect The toner was strictly classified by a classifier to obtain magnetic toner particles. The magnetic toner particles are subjected to a surface treatment by a thermomechanical impact force (processing temperature: 60 ° C.), and the primary particles obtained by subjecting the obtained magnetic toner particles to hydrophobic treatment with 1.8% by mass of silicone oil and hexamethyldisilazane. Dry silica having a diameter of 12 nm (BET specific surface area after treatment: 120 m ² / g) was added and mixed with a mixer to obtain magnetic toner A.

The weight average particle size of the obtained magnetic toner is 6.
7 μm, number average particle size is 5.3 μm, SF-1 is 13
8, SF-2 is 130, BET specific surface area is 5.4 m ² /
cm ³ . The BET specific surface area of the toner particles was 1.8 m ² / cm ³ . Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 2) Magnetic toner B was produced in the same manner as in toner production example 1 except that magnetic iron oxide B of magnetic iron oxide production example 2 was used as the magnetic iron oxide.
I got Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 3) 100 parts magnetic iron oxide C (magnetic iron oxide production example 3) Styrene-butyl acrylate-butyl maleate half ester copolymer (low molecular weight side peak: about 5000, glass transition) (Point Tg: 58 ° C.) 100 parts ・ Chromium complex of monoazo dye (negative charge control agent) 1 part ・ Low molecular weight polyolefin (release agent) 2 parts

The above materials were used, the treatment temperature of the toner particles by thermomechanical impact was set to 64 ° C., and dry silica having a primary particle diameter of 8 nm hydrophobized with silicone oil as inorganic fine powder (BET specific surface area 100 m ² / g)
Of 1.8% by mass and 0.5% by mass of spherical silica (BET)
Magnetic toner C having a weight average particle size of 7.0 μm was obtained in the same manner as in toner production example 1 except that the specific surface area was 20 m ² / g and the primary particle size was 0.1 μm. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 4, 5 and 6) The same procedure as in Toner Production Example 3 was carried out except that the magnetic iron oxides D, E and F of Magnetic Iron Oxide Production Examples 4, 5 and 6 were used as the magnetic iron oxide. Toners D, E and F were obtained. Table 4 shows the physical properties of the obtained magnetic toner.

(Production Example 7 of Toner) 110 parts of magnetic iron oxide G (Production Example 7 of magnetic iron oxide) 100 parts of polyester resin (low molecular weight side peak: about 7000, glass transition point Tg: 63 ° C.) 100 parts of monoazo dye Chromium complex (negative charge control agent) 1 part ・ Low molecular weight polyolefin (release agent) 2 parts

A weight average particle size of 6.6 μm was obtained in the same manner as in Toner Production Example 1 except that the above-mentioned materials were used, and that the processing temperature of the toner particles due to thermomechanical impact was set at 64 ° C.
Magnetic toner G was obtained. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 8 and 9) Magnetic toner H was produced in the same manner as in toner production example 1 except that magnetic iron oxide H of magnetic iron oxide production example 8 was used as the magnetic iron oxide.
Was prepared in the same manner as in Toner Production Example 7, except that magnetic iron oxide H was used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 10) As an inorganic fine powder, a primary particle diameter of 1 which was hydrophobized with 1.8% by mass of silicone oil and hexamethyldisilazane was used.
2 nm dry silica (BET specific surface area 120 m ² / g)
And 0.3% by mass of spherical silica (BET specific surface area 5 m ²
/ G, primary particle size of 1.0 μm), to obtain a magnetic toner J in the same manner as in Toner Production Example 1. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 11) Dry silica having a primary particle diameter of 12 nm (BET specific surface area: 1) treated with hydrophobic treatment of 1.2% by mass of hexamethyldisilazane with respect to the magnetic toner particles obtained in Toner Production Example 1.
60 m ² / g) and mixed with a mixer to obtain Magnetic Toner K. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 12 and 13) As inorganic fine powder, titanium oxide fine particles having a primary particle size of about 20 nm (BET specific surface area: 100 m ² / g) hydrophobized with silicone oil, alumina fine particles having a primary particle size of about 20 nm (BET specific surface area: 90 m ² / g) Magnetic toners L and M were obtained in the same manner as in toner production example 1 except that 1.0% by mass was used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 14) A magnetic toner N was obtained in the same manner as in Toner Production Example 1, except that the surface treatment was not performed by thermomechanical impact. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 15) Magnetic iron oxide A (magnetic iron oxide production example 1) 60 parts Styrene-butyl acrylate copolymer (low molecular weight side peak: about 18,000, glass transition point Tg: 71 ° C.) 100 parts ・ Chromium complex of monoazo dye (negative charge control agent) 1 part ・ Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender,
Melted and kneaded with a twin-screw extruder heated to ℃, the cooled kneaded material is coarsely pulverized with a hammer mill, the coarsely pulverized material is finely pulverized with a jet mill, and the obtained finely pulverized material is multi-divided using the Coanda effect The toner was strictly classified by a classifier to obtain magnetic toner particles. 0.5% by mass based on the obtained magnetic toner particles
Dry silica having a primary particle size of about 16 nm hydrophobized with hexamethyldisilazane (BET specific surface area of 10 after treatment)
0 m ² / g) and mixed with a mixer to form a magnetic toner O
I got The weight average particle size of the obtained magnetic toner O is 12.
It was 7 μm. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 16) A magnetic toner P was obtained in the same manner as in Toner Production Example 1, except that the inorganic fine powder was not added to the toner particles. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 17) In the toner production example 1, dry silica having a primary particle diameter of 12 nm obtained by hydrophobizing inorganic fine powder with 1.8% by mass of silicone oil and hexamethyldisilazane (BE after treatment)
T specific surface area of 120 m ² / g) and dry silica having a primary particle size of 40 nm hydrophobized with 0.5% by mass of hexamethyldisilazane (BET specific surface area of 40 m ² / g after treatment) Magnetic toner Q was obtained in the same manner as in Production Example 1. Table 4 shows the physical properties of the obtained magnetic toner.

[0167]

[Table 3]

<Photoreceptor Production Example 1> A photoreceptor having a diameter of 3
A 0 mm Al cylinder was used as a substrate. Then, layers having the structure shown in FIG. 3 were sequentially laminated by dip coating to prepare a photoreceptor.

(1) Conductive coating layer: Mainly composed of powder of tin oxide and titanium oxide dispersed in phenol resin. The thickness is 15 μm.

(2) Undercoat layer: Mainly composed of modified nylon and copolymerized nylon. The film thickness is 0.6 μm.

(3) Charge generation layer: mainly composed of an azo pigment having absorption in a long wavelength region dispersed in butyral resin. The film thickness is 0.6 μm.

(4) Charge transporting layer: mainly composed of a hole transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight: 20,000 according to the Oswald viscosity method) at a mass ratio of 8:10, and further comprising polytetrafluoroethylene. Powder (particle size: 0.2 μm) was added at 10% by mass based on the total solid content, and dispersed uniformly. 25 μm thick. The contact angle with water was 95 degrees.

The contact angle was measured using pure water, and the apparatus used was a contact angle meter CA-DS, Kyowa Interface Science Co., Ltd.

<Photoreceptor Production Example 2> A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that polytetrafluoroethylene powder was not added. The contact angle with water was 74 degrees.

<Photoreceptor Production Example 3> The photoreceptor was manufactured according to Photoreceptor Production Example 1 up to the charge generation layer. As the charge transport layer, a material obtained by dissolving a hole transporting triphenylamine compound in a polycarbonate resin at a mass ratio of 10:10 was used. Film thickness 20 μm. Further, as a protective layer, a polytetrafluoroethylene powder (particle diameter: 0.2 μm) was added to a composition in which the same material was dissolved at a mass ratio of 5:10, and 30% of the total solid content was added thereto. Was spray-coated on the charge transport layer. Film thickness 5 μm. The contact angle with water was 102 degrees.

Example 1 The image forming apparatus shown in FIGS. 1 and 2 was used.

Using the organic photoconductor (OPC) drum of Photoconductor Production Example 3 as the electrostatic latent image carrier, the dark portion potential V _d = −70.
0 V and the bright portion potential V _L = −210 V. A gap between the photosensitive drum and the developing sleeve is set to 300 μm, and a resin layer having a thickness of about 7 μm and a JIS center line average roughness (Ra) of 0.8 μm having the following structure is used as a toner carrier. Using a developing sleeve formed on an aluminum cylinder, a developing magnetic pole of 95 mT (950 gauss), a urethane rubber blade having a thickness of 1.0 mm and a free length of 10 mm as a toner regulating member, 14.7 N / m (15 g / cm)
At a linear pressure of.

Phenol resin 100 parts Graphite (particle size: about 7 μm) 90 parts Carbon black 10 parts

Next, as a developing bias, a DC bias component V _dc = −500 V, and a superimposed AC bias component V
_PP = 1200 V and f = 2000 Hz were used. Also,
The peripheral speed of the developing sleeve is the peripheral speed of the photoconductor (48 mm / sec)
150% in the forward direction (reverse direction of rotation)
(72 mm / sec).

Also, as shown in FIG. 7, a transfer roller (made of ethylene-propylene rubber in which conductive carbon is dispersed, the volume resistivity of the conductive elastic layer is 10 ⁸ Ωcm, and the surface rubber hardness is 24
°, diameter 20 mm, contact pressure 49 N / m (50 g / cm)
Is constant with respect to the peripheral speed of the photoconductor (48 mm / sec),
+2000 V was applied as a transfer bias, and magnetic toner A was used as a toner, and an image was formed under an environment of 23 ° C. and 65% RH. 75 g / m ² paper was used as the transfer paper.

At this time, the transfer efficiency from the photoreceptor to the transfer material was as high as 96%, and a good image was obtained without any missing characters or lines during the transfer and without scattering on the image.

In the present invention, the scattering is evaluated as follows.
This is a splattering evaluation with a fine thin line related to the image quality of a graphical image, and a splattering evaluation with a 100 μm-wide line which is more sparse than a character or a line.

The transferability was evaluated by tapping and removing the transfer toner on the solid black photoreceptor with Mylar tape, and subtracting the Macbeth density of the tape-only tape from the Macbeth density of the tape. did.

Further, images were continuously output on up to 1000 sheets even under a low-temperature and low-humidity environment of 15 ° C. and 10% RH. However, the toner coat on the toner carrier was uniform and a good image without image defects was obtained. Obtained.

Example 2 An image was formed using the same apparatus and under the same conditions as in Example 1 except that the OPC drum of Photoconductor Production Example 1 was used as the electrostatic latent image carrier. At this time, the transfer efficiency from the photosensitive member to the transfer material is 93.
%, A good transfer efficiency was obtained, and a good image was obtained without any missing characters or lines during transfer and without scattering on the image. A good image free from image defects was obtained in a continuous image printing test under a low-temperature and low-humidity environment in the same manner as in Example 1.

Example 3 An image was formed using the same apparatus and conditions as in Example 1 except that the toner B of Toner Production Example 2 was used as the toner.

At this time, the transfer efficiency from the photoreceptor to the transfer material was as high as 95% and 96%, and a good image was obtained without any missing characters or lines during transfer and no scattering on the image. Was. In a continuous image printing test under a low-temperature and low-humidity environment, a good image free of image defects similar to that of Example 1 was obtained.

Comparative Example 1 An image was formed under the same apparatus and conditions as in Example 1 except that the toner H of Toner Production Example 8 was used as the toner. As a result, the transfer efficiency from the photoreceptor to the transfer material was almost good, but continuous transfer under a low-temperature and low-humidity environment of 15 ° C. and 10% RH.
In the 000-sheet image test, at the end of the test, the developability was slightly inferior to that of Example 1 and the image density was lower. Further, in a solid image after continuous printing of 1000 sheets under a low-temperature and low-humidity environment, unevenness in image density caused by poor toner coating on a toner carrier was caused.

Examples 4 to 7 As a black toner carrier, a layer having a thickness of about 7 μm and a JI
A developing sleeve was prepared in which a resin layer having an S center line average roughness (Ra) of 1.5 μm was formed on a stainless steel cylinder having a diameter of 16φ and a blasted surface.

・ Phenol resin 100 parts ・ Graphite (particle size: about 3 μm) 45 parts ・ Carbon black 5 parts

The developing sleeve and the magnetic toners C, D, E, and F of Toner Production Examples 3 to 6 were used as the black toner, and the DC bias component Vdc = -500 as the developing bias.
V, superimposed AC bias component Vpp = 1100V, f
= 2000 Hz, and an image was produced using the same apparatus and conditions as in Example 1 except that the developing sleeve was rotated in the forward direction with the ratio Vt / V of the peripheral speed Vt of the developing sleeve to the peripheral speed of the photosensitive member being 2.0.
As a result, the transfer efficiency from the photoconductor to the transfer material is 9
High transfer efficiency of 6%, 97%, 98%, 98%
In each case, the transfer efficiency was as good as or better than that of Example 1, and a good image with no missing characters or lines during transfer and no scattering on the image was obtained.

In the continuous image output test for 1,000 sheets in a low-temperature and low-humidity environment of 15 ° C. and 10% RH, all showed good developability.
In the case of E and F, the image density was higher. In particular, in the case of the magnetic toners E and F, the uniformity was high even after continuous printing of 1000 sheets under a low-temperature and low-humidity environment, and a high-quality solid image was obtained.

Comparative Example 2 An image was formed under the same apparatus and conditions as in Example 1 except that the toner I of Toner Production Example 9 was used as the magnetic toner. As a result, although the transfer efficiency from the photosensitive member to the transfer material was slightly worse than that in Example 1, it was almost good.
In a continuous 1000-sheet image output test in a low-temperature and low-humidity environment of 10 ° C. and 10% RH, at the end of the test, the developability was slightly inferior to Example 1 and the image density was lower. Further, in a solid image after continuous printing of 1000 sheets under a low-temperature and low-humidity environment, unevenness in image density caused by poor toner coating on a toner carrier was caused.

Example 8 An image was formed under the same apparatus and conditions as in Example 1 except that the magnetic toner G of Toner Production Example 7 was used as the toner.
As a result, the transfer efficiency from the photoreceptor to the transfer material was 94%, and the transfer efficiency was almost the same as in Example 1. A good image was obtained with no missing characters or lines during transfer and no scattering on the image. Was. In addition, even under a low-temperature and low-humidity environment, the toner coatability was good, the developability and the durability were good, and the solid image had high uniformity without image defects.

Example 9 The magnetic toner J of Toner Production Example 10 was used as the toner, and the DC bias component Vdc = -4 was used as the developing bias.
50 V, superimposed AC bias component Vpp = 1300
An image was formed using the same apparatus and conditions as in Example 1 except that V and f were set to 2000 Hz, and the transfer efficiency from the photosensitive member to the transfer material was 96%, which was the same as or better than that in Example 1. Shows efficiency, no missing characters and lines during transfer,
A good image without scattering on the image was obtained. Also,
Even in a low-temperature and low-humidity environment, stable toner coatability and good developability and durability were exhibited, and a solid image was also highly uniform without image defects.

Example 10 An image was formed under the same apparatus and conditions as in Example 1 except that the magnetic toner K of Toner Production Example 11 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material was 94%.
In the same manner as in Example 1, a good image with good transfer efficiency, no missing characters or lines during transfer, and no scattering on the image was obtained. In addition, even under a low-temperature and low-humidity environment, the toner coatability was good, the developability and the durability were good, and the solid image had high uniformity without image defects.

Example 11 An image was formed using the same apparatus and conditions as in Example 1 except that the magnetic toner L of Toner Production Example 12 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material was 92%.
The transfer efficiency is good and there is no omission during transfer of characters and lines,
A good image without scattering on the image was obtained. Also,
Even in a low-temperature and low-humidity environment, stable toner coatability and good developability and durability were exhibited, and a solid image was also highly uniform without image defects.

Example 12 An image was formed using the same apparatus and conditions as in Example 1 except that the magnetic toner M of Toner Production Example 13 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material is 90%.
The transfer efficiency is good and there is no omission during transfer of characters and lines,
A good image without scattering on the image was obtained. Also,
Even in a low-temperature, low-humidity environment, the toner coatability was good, the developability and durability were good, and the solid image had high uniformity without image defects.

Comparative Example 3 An image was formed using the same apparatus and conditions as in Example 2 except that the toner N of Toner Production Example 14 was used as the toner. As a result, the transfer efficiency from the photoreceptor to the transfer material was 85%, and the transfer efficiency was lower than that of Example 2, and the image was somewhat missing during the transfer of characters and lines.

Comparative Example 4 An image was formed under the same apparatus and conditions as in Example 2 except that the magnetic toner O of Toner Production Example 15 was used as the toner. As a result, an image was obtained in which the transfer efficiency from the photosensitive member to the transfer material was 83%, which was slightly inferior to the transfer efficiency compared to Example 2 and the transfer characteristics of the characters and lines were somewhat conspicuous during the transfer. Was done. Further, although the image density was stable even when continuously used in a low-temperature and low-humidity environment, an image having a lower image density was obtained as compared with Example 1.

Comparative Example 5 The magnetic toner P of Toner Production Example 16 was used as the toner.
An image was formed using the same apparatus and conditions as in Example 1 except that the OPC drum of Photoconductor Production Example 2 was used as the electrostatic latent image carrier. As a result, the transfer efficiency from the photosensitive member to the transfer material was 74%, the transfer efficiency was lower than that in Example 1, and some missing characters and lines were missed during the transfer.

Although continuous use in a low-temperature and low-humidity environment did not cause image defects such as uneven shading of a solid image, the image density tended to decrease.

Example 13 An image was formed using the same apparatus and conditions as in Example 1 except that the toner Q of Toner Production Example 17 was used as the toner.
At this time, the transfer efficiency from the photoreceptor to the transfer material was as high as 96%, and a good image was obtained without any missing characters or lines during the transfer and no scattering on the image.

[0204]

According to the present invention, in a toner having toner particles containing at least a binder resin and magnetic iron oxide and an inorganic fine powder, the magnetic iron oxide is obtained by converting (a) silicon element with iron element as a standard. 0.4 to 4% by mass or (b) 0.05 to 10% by mass of aluminum based on iron, or both silicon and aluminum in the above proportions, The value of the shape factor SF-1 measured by the image analyzer is 110 <SF-1 ≦ 180,
The value of the shape factor SF-2 is 110 <SF-2 ≦ 140, the value of the ratio B / A is 1.0 or less, and the BE of the toner is
Specific surface area per unit volume Sb measured by T method
(M ² / cm ³ ) and the specific surface area St (m) calculated from the weight average particle diameter when the toner is assumed to be a true sphere.
² / cm ³ ) satisfying the following condition: 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5 An electrophotographic apparatus having a developing step of forming a toner image using the toner and a transfer step of transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material. By using the image forming method to be used, it is possible to improve omission during transfer and transfer efficiency while maintaining high image density and latent image reproducibility. further,
The toner charge controllability is improved more than before, and even with continuous image formation in a low-temperature and low-humidity environment, the uniformity of the thin toner layer coat on the toner carrier can be obtained, and unevenness such as blurring / wavy unevenness on a solid image can be obtained. A high-quality and sharp image without image defects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus suitable for the present invention.

FIG. 2 is a schematic diagram illustrating an example of a developing device for one-component development.

FIG. 3 is a schematic diagram illustrating an example of a configuration of a photoconductor used in the present invention.

FIG. 4 is a schematic diagram of a charge amount measuring device for measuring a charge amount of a toner used in the present invention.

FIG. 5 is a diagram showing a good image (a) without “transfer missing” and a bad image (b) having “transfer missing”.

FIG. 6 is a diagram showing a range of the present invention in shape factors SF-1 and SF-2.

FIG. 7 is a schematic view illustrating an example of a contact transfer member.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 photoconductor (electrostatic latent image carrier) 102 developing sleeve (toner carrier) 103 contact blade 104 magnet roller 114 transfer charging roller 116 cleaner 117 primary charging roller 140 developing device 141 stirring bar

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI G03G 9/08 372 G03G 9/08 374 374 375 375 301 15/08 507 15/08 507L (72) Inventor Keita Nozawa Ota, Tokyo 3-30-2 Shimomaruko-ku Canon Inc. (72) The inventor Yuki Nishio 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (56) References JP-A-6-194869 (JP, A) JP-A-7-72654 (JP, A) JP-A-5-333594 (JP, A) JP-A-4-190242 (JP, A) JP-A-61-279864 (JP, A) JP-A-1 JP-A-185654 (JP, A) JP-A-3-248162 (JP, A) JP-A-4-162050 (JP, A) JP-A-4-162048 (JP, A) JP-A-62-174772 (JP, A) ) JP-A-2-43564 (JP A) JP-A-2-59768 (JP, A) JP-A-4-2044751 (JP, A) JP-A-4-44051 (JP, A) JP-A-7-64327 (JP, A) JP-A-4 -188157 (JP, A) JP-A-5-249742 (JP, A) JP-A-6-250413 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 G03G 5/00

Claims (31)

(57) [Claims] 1. A toner comprising an inorganic fine powder and toner particles containing at least a binder resin and magnetic iron oxide, wherein the magnetic iron oxide has (a) 0.4 to 4 mass% of silicon element based on iron element. % And on the outermost surface of magnetic iron oxide
Fe / Si atomic ratio of 1.2 to 4.0 or (b) containing 0.05 to 10% by mass of aluminum element based on iron element , and Fe / Al atoms on the outermost surface of magnetic iron oxide
The ratio is 0.3 to 10.0, or (c) both a silicon element and an aluminum element are contained in the above ratio, and
Fe / Si atomic ratio and Fe / Al on the outermost surface of iron fossil
The atomic ratio is within the above range, and the value of the shape factor SF-1 of the toner measured by the image analyzer is 110 <SF-1 ≦ 180, and the shape factor SF−
2 is 110 <SF-2 ≦ 140, and the ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 1. 0 or less, the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method, and the weight per unit volume calculated from the weight average particle size when the toner is assumed to be a true sphere. A toner characterized in that the relationship of the specific surface area St (m ² / cm ³ ) satisfies the following condition: 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5 Wherein the ratio of the total content a of silicon element content b and magnetic iron oxide of silicon elements iron element dissolution ratio of the magnetic iron oxide is present in up to 20 wt% (b / a) × 100 is 44 ~
84%, which is the ratio of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element (c / a) ×
Claim 1 100 is characterized in that a 10 to 55%
The toner according to. 3. The toner according to claim 1 or 2 wherein the toner is characterized in that per 100 parts by weight of the binder resin, a magnetic toner containing organic magnetic material 30 to 200 parts by weight. 4. The SF of the toner measured by an image analyzer.
Value of -1 is 120 to 160, and claims 1 to 3 the value of SF-2 is characterized in that it is a 115 to 140
The toner according to any one of the above. 5. The inorganic fine powder contained in the toner is titania, alumina, silica or the claims 1 to 4, characterized in that one or more kinds of inorganic fine powder selected from among the mixed oxide The toner according to any one of the above. 6. The method of claim inorganic fine powder contained in the toner is characterized in that which is hydrophobized 5
The toner according to 1. 7. The toner according to claim 6 , wherein the hydrophobized inorganic fine powder contained in the toner has been treated with at least silicone oil. 8. The inorganic fine powder contained in the toner,
The primary particle size is 30 nm or less, and the toner has a primary particle size of 30 nm or less.
The toner according to any one of claims 5 to 7 , further comprising a fine powder having a particle diameter exceeding nm. 9. The toner according to claim 8 , wherein the fine powder having a size exceeding 30 nm is an inorganic fine powder. 10. The toner according to claim 8 , wherein the fine powder having a size exceeding 30 nm is a resin fine powder. 11. A fine powder of more than the 30nm, the toner according to any one of claims 8 to 10, characterized in that it is substantially spherical. 12. The low molecular weight peak in the molecular weight distribution of the toner measured by GPC is from 3,000 to 150.
The toner according to any one of claims 1 to 11 , wherein the toner is in the range of 00. 13. The toner particles have a specific surface area per volume measured by a BET method of 1.2 to 2.5 m ² / c.
The toner according to any one of claims 1 to 12, characterized in that it is m ^3. 14. The toner particle according to claim 1, wherein a 60% pore radius in a cumulative pore area ratio curve of pores of 1 nm to 100 nm is 3.5 nm or less.
3. The toner according to any one of 3 . 15. A developing step of forming a toner image on an electrostatic latent image carrier, and transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material. In an image forming method using an electrophotographic apparatus having a process, the toner is a toner having toner particles containing at least a binder resin and a magnetic iron oxide and inorganic fine powder, and the magnetic iron oxide comprises (a) a silicon element. Is contained in an amount of 0.4 to 4% by mass based on the iron element , and on the outermost surface of the magnetic iron oxide.
Fe / Si atomic ratio of 1.2 to 4.0 or (b) containing 0.05 to 10% by mass of aluminum element based on iron element , and Fe / Al atoms on the outermost surface of magnetic iron oxide
The ratio is 0.3 to 10.0, or (c) both a silicon element and an aluminum element are contained in the above ratio, and
Fe / Si atomic ratio and Fe / Al on the outermost surface of iron fossil
The atomic ratio is within the above range, and the value of the shape factor SF-1 of the toner measured by the image analyzer is 110 <SF-1 ≦ 180, and the shape factor SF−
2 is 110 <SF-2 ≦ 140, and the ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 1. 0 or less, and the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method and the weight average particle size per unit volume calculated from the weight average particle size when the toner is assumed to be a true sphere An image forming method, wherein the relationship of the specific surface area St (m ² / cm ³ ) satisfies the following condition: 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5. 16. The ratio of the total content of a silicon-element content b and magnetic iron oxide of silicon elements iron element dissolution ratio of the magnetic iron oxide is present in up to 20 wt% (b / a) × 100 is 44
And a ratio (c / a) of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element.
X100 is 10 to 55%.
Item 15. The image forming method according to Item 15 , To 17. The toner binder resin 100 parts by weight, the image forming method according to claim 15 or 16, characterized in that the magnetic 30 to 200 parts by mass which is a magnetic toner containing chromatic. 18. The S of the toner measured by an image analyzer.
The image forming method according to any one of claims 15 to 17 , wherein the value of F-1 is 120 to 160, and the value of SF-2 is 115 to 140. 19. inorganic fine powder contained in the toner is titania, alumina, silica or the claims 15 to 18, characterized in that one or more kinds of inorganic fine powder selected from among the mixed oxide The image forming method according to any one of the above. 20. The method according to claim 20, wherein the inorganic fine powder contained in the toner has been subjected to a hydrophobic treatment.
20. The image forming method according to 19 . 21. The image forming method according to claim 20 , wherein the hydrophobized inorganic fine powder contained in the toner has been treated with at least silicone oil. 22. The inorganic fine powder contained in the toner has a primary particle size of 30 nm or less, and the toner
22. The image forming method according to claim 15 , further comprising a fine powder having a size exceeding 30 nm. 23. The image forming method according to claim 22 , wherein the fine powder having a size exceeding 30 nm is an inorganic fine powder. 24. The image forming method according to claim 22 , wherein the fine powder having a size exceeding 30 nm is a resin fine powder. 25. fine powder exceeding the 30nm, the image forming method according to any one of claims 22 to 24, characterized in that practically spherical. 26. In the molecular weight distribution of the toner measured by GPC, the peak on the low molecular weight side is 3000 to 150.
Claim, characterized in that in the range of 00 15 to 25
The image forming method according to any one of the above. 27. The toner has a specific surface area per volume of 1.2 to 2.5 m ² / c measured by a BET method.
The image forming method according to any one of claims 15 to 26, characterized in that it is m ^3. 28. The toner according to claim 15 , wherein a 60% pore radius in a cumulative pore area ratio curve of pores of 1 nm to 100 nm of the toner particles is 3.5 nm or less.
28. The image forming method according to any one of 27 . 29. A contact angle of the surface of the electrostatic latent image carrier is 8
The image forming method according to any one of claims 15 to 28, characterized in that at 5 degrees or more. 30. The image forming method according to claim 29 , wherein the surface of the electrostatic latent image carrier contains a substance containing fluorine. 31. The image forming method according to claim 30 , wherein the substance containing fluorine on the surface of the electrostatic latent image carrier is a fine powder containing fluorine.